Cartilage on articular surfaces of bones at joints within a body provide important protection for the underlying bone. Portions of the bone supporting the articular cartilage are typically referred to as sub-chondral bone. Both acute and chronic injury of articular cartilage causes chondral defects, which can lead to progressive joint pain and impaired mobility.
Various remedies exist to address chondral defects, such as a surgical procedure including microfracture. Microfracture involves selective perforation of sub-chondral bone. Numerous studies show that microfracture beneath a chondral defect can result in a blood clot filling the chondral defect with pluripotent marrow-derived mesenchymal stem cells that produce beneficial fibrocartilage repair tissue.
In a microfracture procedure, a surgeon typically debrides unstable cartilage down to the sub-chondral bone layer to support subsequent basilar integration of the new repair tissue. Microfracture can be accomplished thereafter using one or more rigid, curved awls that are manually manipulated through arthroscopic access sheaths or cannulas, and sometimes struck with a mallet, to create a series of microfracture holes in sub-chondral bone. Working space at chondral defects is usually limited, and it is difficult to manipulate the awls effectively, especially within hip joints. A surgeon may need to exchange awls of different curvatures at different stages of the procedure, which can lengthen a time of the surgical procedure. Additionally, the cutting tips of the awls are exposed during insertion and withdrawal from the body as well as during use on bone, which can result in cuts and/or other damage to tissue and/or other material by which the awl passes during insertion and withdrawal. Skiving of the awl's tip across bone, for example, can cause longitudinal disruptions and potential weakening of sub-chondral bone.
Accordingly, there remains a need for improved methods and devices for forming holes in bone to stimulate bone growth.